In a variety of applications, it is necessary to form liquid-tight seals between an electrical power cable and a component. For example, in subsurface production of liquids, such as oil, it may be necessary to provide electrical power to an electric submersible pumping system. Typically, a power cable is run downhole and connected to a submersible electric motor. The electric motor is powered to turn a centrifugal pump that intakes the production fluid and raise it or move it to a desired location, such as the surface of the earth.
In such applications, the electric submersible pumping system often is utilized within a wellbore at a location deep beneath the surface of the earth. In that type of environment, components are subjected to extreme pressures, extreme temperatures, and often corrosive environments. Thus, it can be difficult to form a lasting, fluid-tight seal between the power cable and the submersible component, e.g. submersible motor.
In conventional connectors, e.g. potheads, the conductors of the power cable are disposed through a connector housing and through the outer housing of the submersible component for appropriate connection. Within the connector housing, a plurality of blocks are used to support the individual conductors. Typically, an elastomeric block or blocks is disposed between a pair of relatively hard blocks. The hard blocks are utilized to squeeze the elastomeric block until it forms a seal between the individual conductors and the interior surface of the connector housing. Additional elastomeric seals are used to prevent fluid flow between the connector and the submersible component housing.
The elastomers used to form the seals are subject to degradation from thermal exposure, compression set due to thermal cycling (i.e. system starts and stops), and H2S gas transmission. When providing power in an environment having very high operating temperatures, the seals expand and exert great pressure on the conductor insulation which can result in the insulation tearing and opening a path to ground.
There exists, therefore, a need for a high temperature pothead that does not utilize elastomeric seals.